Powering a furnace

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infinity

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Staff member
Location
New Jersey
Occupation
Journeyman Electrician
As long as it attaches to the furnace with an appropriate NM connector and the EGC is terminated properly it's code compliant. Still sloppy in my book.
 

iwire

Moderator
Staff member
Location
Massachusetts
And mine is connected with portable cord. That seems to be big in CA, maybe for the disconnect?
The receptacle is a combo single receptacle and screw-in fuse holder.

In most areas that is a violtion but I do understand it is standard practice in some areas.

The NEC requires the appliance be listed for code and plug connection, I don't believe furnaces are.
 

Cavie

Senior Member
Location
SW Florida
Needs a disconnect. Maybe there just not in the picture. Yep, that's how it's done. Nothing in the NEC about conduit needed at a certain height.
 

PetrosA

Senior Member
Needs a disconnect. Maybe there just not in the picture. Yep, that's how it's done. Nothing in the NEC about conduit needed at a certain height.

There may be nothing about conduit needed at a certain height, but there is something in the NEC about protection from mechanical damage being needed below a certain height. Around here you would only ever see AC, MC or conduit down to the heater or indoor unit.
 

jap

Senior Member
Occupation
Electrician
Most units have the Factory Wiring brought to a wiring compartment so its not quite so ugly.
 

Smart $

Esteemed Member
Location
Ohio
There is nothing specifically about height and damage in the NEC that applies to this installation.
I will add that NM cable is typically permitted to be run exposed in normally dry locations of dwelling units.
 

PetrosA

Senior Member
I agree there's no exact height given, but one can be inferred. 334.15 talks about exposed NM and it either has to (A) follow the surface of the building or be mounted on a running board, which the wire to a heater is not, or (B) it shall be protected from physical damage where necessary or (C) it shall be protected according to 300.4 or it's up in the framing or it's in protection down the walls. (C) is where we can infer the height (below and out of the framing which offers protection from damage). That leaves (B) which requires protection from physical damage, which surface mounting on the heater unit or ty-rapped to the gas pipe feeding the heater doesn't really offer. Sure, the line is fuzzy. If the wiring stops at five feet (like for a water heater or feeding into the top of a designated sub panel for the heater) you could consider it to be sufficiently protected, but taking it all the way down to the lower section of a heater, just like mounting a receptacle on a brick column in a basement should require protection.
 

iwire

Moderator
Staff member
Location
Massachusetts
I agree there's no exact height given, but one can be inferred. 334.15 talks about exposed NM and it either has to (A) follow the surface of the building or be mounted on a running board, which the wire to a heater is not, or (B) it shall be protected from physical damage where necessary or (C) it shall be protected according to 300.4 or it's up in the framing or it's in protection down the walls. (C) is where we can infer the height (below and out of the framing which offers protection from damage). That leaves (B) which requires protection from physical damage, which surface mounting on the heater unit or ty-rapped to the gas pipe feeding the heater doesn't really offer. Sure, the line is fuzzy. If the wiring stops at five feet (like for a water heater or feeding into the top of a designated sub panel for the heater) you could consider it to be sufficiently protected, but taking it all the way down to the lower section of a heater, just like mounting a receptacle on a brick column in a basement should require protection.

I disagree with that and luckily for me so do seemingly all inspectors in the New England area.

We run exposed NM like that all the time.

You will often see exposed NM down low supplying water heaters, garbage disposers, even outlets on basement walls. A running board is installed and the NM run down it.
 

PetrosA

Senior Member
I disagree with that and luckily for me so do seemingly all inspectors in the New England area.

We run exposed NM like that all the time.

You will often see exposed NM down low supplying water heaters, garbage disposers, even outlets on basement walls. A running board is installed and the NM run down it.

Running boards for outlets on basement walls were used around here, but their use stopped back in the 60s or so. Water heaters are usually fed with NM, but it's not usually low enough or exposed enough to get damaged. Disposers are an interesting anomaly - here in the Lancaster area they and dishwashers are all direct-wired. Go east towards Philly and you won't find a disposer or dishwasher hardwired at all. They all have cords. Any hard wiring in the sink base (or other base cabinets, if exposed to damage) will have to have a sleeve for protection or you don't pass inspection.

I guess I can see how the inspectors up there could interpret the code to allow exposed NM down to a heater or even on a basement wall, but I personally wouldn't install it like that. At that point, what's the use of installing a running board since it's not specifically required by code? You can just use NM straps on the brick, block or stone. If you want to go cheap, go really cheap.
 
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